Electrode for electrolytic cells



Jan. 27, 1931.

K. Ro'rH v ELECTRODE FOR ELECTROLYTIC CELLS Filed Jan. 21, 1926 v 2Sheets-Sheet 1 n; f 1 III e o o e o o o 0 000 00000 0 0 000 00000 0 e oo o o o. o o o o o o o e o o o o 0 9a 0 00 000 o o o o o o o o o a o o oo 4 00 0000 INVENTOR Karl R0 2%.-

4, m ORNEYS' Fig.3,

Jan; 27 1931.

V ROTH ELECTRODE FOR ELECTROLYTIC CELLS Filed Jan. 21 1926 2Sheets-Sheet 2 m 1 l l III Patented J... 27, 1931 UNITED STATESPATE-NT'OFFICE.

mIl OI LUDWIGSHAIEN-ON-THE-BHINE, GERMANY, ASSIGNOR TO IIG. 113- UBTBIEAKTIENGEBELLSOEAF'I', OI IRANKIORT-ON-TEE-MAIN, GERMANY,

A OQBPORATION OI GERMANY ELECTRODE FOB. ELEOTRQLYTIO CELLS Applicationfled January 21, 1928, Serial No. 82,781, and in Germany January 22,1925.

' The present invention relates to electrodes for the electrolyticdevelopment of gases, especially by the decomposition of water.

My improved electrodes have the advantage that the formation of foamfrom the electrolyte and the fine gas bubbles formed is avoided to agreat extent and units of high capacity can be constructed on acomparatively small floor area. 7

My invention will be explained with reference to the accompanyingdrawings which, however, are diagrammatical and to which I do notwish tolimit my invention.

Fig. 1 shows a vertical section of one form of my improved electrode.Fig. 2 shows a front perspective view thereof partly broken away. Fig. 3shows a vertical section of a modified form of my electrode. Fi 4- is afront perspective view of same. F1gs.'5,. 6

and 7 are vertical sectional views of some other modifications of myelectrode.

The electrode according to my invention consists of a number of pocketsa arranged one upon anotherin one or several series.

The front wall (I) in Figure 1) of the pockets fronting thecounter-electrode or the diahragm between the two electrodes is made ommetal provided with suitable openings to allow the passage of gas as forexample borings or slits, or it may be made from wire-mesh. If bothsides of the electrode are to be used for electrolysis, either as adouble-side unipolar or as bipolar electrode, beth the frontandback-wall of the pocket must be made of metal and permeable for thegases. If only one side is used for electrolysis the pockets arepreferably also made wholly of metal though this is not necessary.

The bulk of the gas is developed in the form of fine bubbles at theouter surface of the electrode, part of which passes through theopenings of the electrode wall to the interior of the pocket. The restof the gas bubbles is forced into .theinterior by suitable guidingdevices, for example by horizontal partitions 72. between the electrodeand the diaphragm i (see Figure 6) which at the same time may serve assupports for the diaphragm. The partitions may be made 60 of anymaterial resistant to the actlon of the electrolyte. The distancebetween the said partitions and the upper edges of the pockets may varyin accordance with the construction of the ,walls of the pockets,

The gases collected in each pocket are led off through the upper wall ofthe pocket in any suitable manner and are generally intro! duced intothe next higher pocket. The pipes or channels leading the gases ofi mayhave any desired cross-section, and preferably their lower end extends alittle into the upper part of the lower pocket, the walls of which arecorrespondingly left impermeable to gases in their upper, part. By thisconstruction, .the fine gas bubbles rising within the pockets are forcedto collect near the top of them to a kind of gas cushion. As soon asadditional gas causes said gas cushion to ex ceed the. extension of thepipes or channels into the pocket, .gas is discharged in the-form of bigbubbles through all upper pockets. Thereby theformation of a thlckemulsion of the electrolyte with the fine gas bubblesis prevented whichnot only would give rise to a foam, but would be liable to run back tothe outside of the pocket and on account of its reduced conductivitywould increase the resistance of the cell. As the quantity of gasincreases from below to above, it may be advantageous to increase thenumber or the ,cross section of the gas leading pipes or channels in theupper pockets. In some cases it appears convenient not to pass the biggas bubbles successively through all of the upper pockets, but directlyinto the uppermost one or to the collecting pipe whether by means ofpipes or outside said pockets in the spaces between the pockets or forexample by prolonged pipes or channels directly running through severalof these pockets as indicated in- Figure 7 en gas is discharged from thecushion in a pocket, the bubbles would drag along considerablequantities of the electrolyte contained in that pocket. The resultingvacuum I would cause at once fresh electrolyte to be sucked in fromother pockets, whereby a mix-- ture of the electrolyte'from severalpockets in the system is caused; This circulation may be assisted bysuitable pipes or channels f i and gwhich must not necessarily connectverenlarging their size.

.anolyte and catholyte may be assisted by arranging the anode pocketsand cathode pockets fronting one diaphragm in a vertically staggeredrelation to each other. 1

The uppermost pockets may be built as chief as collecting chambers (seeFigures 2 and 4 For this purpose, the upper parts of their side wallsmust be impermeable to gas.

The hereinbefore described electrode has the advantage that it may bebuilt as a unit for nearly any desired capacity by assembling therequired number of pockets in vertical and horizontal direction withoutany d'ificulties, as would be caused with other ce Is by The electrodesmay be constructed in many difierent ways. Instead of using one layer ofpockets, there may be two layers with their .back sides against eachother (see Figures 3 and 4) so as to obtain a double-side electrode(Figures 4- and 7) which may be used as a unipolar or as a bipolarelectrode. In the latter case, care must be taken that the electrodealso secures a separation of the electrolytes and gases of the twoadjacent compartments which may be efiected by'suitable tightenings 7a(Figure 7) between the pockets.

, The pockets of an electrode can be made all or-in groups of one or afew single pieces, for 1 example of a casting, the front walls ofperforated sheet-metal or of wire-mesh or the like being put onafterwards and connected metal to metal to secure good electricconductivity; By this manner of production the metallic contact of thefront walls the source of current is easily-efiected.

In the case of bipolar electrodes the tightening walls betweenlthepockets may be made of one piece with the frame. Double side unipolarelectrodes (Figures 5 and 6) may be made of one layer ofupocl rets withperforated frontand back-walls so as to allow the gases to enter intothe pockets.

Or, all pockets may be surrounded by a wall common to all which means anelectrode consisting of a great chamber divided into a 1 number ofpockets by horizontal and vertical walls. The horizontal walls areprovided with pipes or channels, as described above, so as to form ascollecting rooms, and may also be provi ed with pipes for circulatingthe electrolyte exactly as'when using separate pockets. Figure 6showsone form of.

such electrodes.

An arrangement in which two double-side bipolar electrodes are separatedfrom each other by a diaphragm 'i-and in whichhorizontal partitions hfor forcing the gas bubbles into the interior of the electrode pocketsare provided, is shown in Figure 8.

Automatical devices may be arranged for a supply of waterfor thatconsumed during the electrolysis so as to maintain a certain quantity ofelectrolyte in each ,cell. In order to enable a'cooling which whenworking at great outputs may become necessary, suitable hollow spacesare provided in or between some of the pockets apart from the roomcontaining the electrolyte and filled with a cool ing liquid.

. I do not claim in this application a doubleside unipolar electrode inaccordance with my invention specifically, such being claimed in anotherapplication which has been divided out fromthe present one.

I claim! 1. 'An electrode for the electrolytic development of gases,which consists in a structure comprising a number of pockets arrangedone upon another and having metal front-walls permeable to gas andconnection ,pipes between the pockets for leading the gases upwardswhich pipes extend. a little into the upper part of a lower pocket.

2. An electrode for the electrolytic development. of gases, whichconsists in a struc-- ture comprising a number of pockets arranged oneupon another and having metal front-walls permeable to gas andconnection pipes between the pocketsfor leading he gases upwards whichpipes extend a li tle into the upper part of a lower pocket, andseparate pipes for circulating'the electro- 3. An electrode for theelectrolytic development of gases, which consists in a structurecomprising a number of pockets arranged one upon another and havingmetal front-walls permeable to gas and connection pipes between thepockets for leading the gases-upwards, which pipes extend a little intothe upper part of-a lower pocket, and

separate pipes for circulating the electrolyte,

the upper edge of the front-wall of each pocket being provided with aguiding device forcing gas bubbles into the interior of the F pocket. I

'4. An electrode for the electrolytic development of gases, whichconsists in a structure comprising a number of pockets arranged one uponanother and having metal front-walls permeable to gas and connectionpipes between the pockets forleading the gases" upwards, which. pipesextend a little into the upper part ofa lower pocket, and separate.pipes for circulating the electrolyte, the upper part of the front-wallof the highest pocket of a vertical series being impermeable to gas. e

5. An electrode for the electrolytic develr opment of gases, whichconsists in a structure comprising a frame divided by partitions into anumber .of pockets, said pockets'being provided with metal front-wallspermeable to gas and connection pipes between the pockets for leadingthegases upwards which pipes extend a little into the x I supper part ofa lower pocket, and separate p1pes for circulating the, electrolyte. 6.An'electrode for the electrolytic development of gases, which consistsin a structure comprising a number of pockets arranged one uponanothrand in two layers 1 with theirback walls against each other;thepockets having metal front-walls permeable to gas and connection pipesbetween the pockets for leading the gases upwards which pipesextend alittle into the upper part of a lower pocket, and separate p1pes forcirculating the electrolyte. 7. A bipolar electrode for the electrolyticdevelopment of gases, which consists in a structure comprising .a numberof pockets arranged one upon another and in two layers with their backwalls against each other and which are separated by animpermeable wall,the pockets having metal front-walls permeable to gas and connectionpipes between the pockets for leading the gases upwards which pipesextend a little into the upper part of a lower pocket, and separatepipes for circulating the electrolyte. In testimony whreof I havehereunto'set my hand. L ROTH

